Redundant resistive touch panel

ABSTRACT

A touch panel assembly adapted to reduce electromagnetic interference is disclosed. An electronic display is provided within a housing for an instrument panel of a vehicle. A resistive touch panel includes first and second independently operable, seamless grid sections and touch input receivers placed adjacent to the grid sections. A first input/output device in electronic communication with the display and associated with the first grid section and a second input/output device in electronic communication with the display and associated with the second grid section extends through at least one electromagnetically shielded channel that extends from within said housing to outside of said housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/915,367 filed Jun. 29, 2020, which is a continuation of U.S.application Ser. No. 16/547,657 filed Aug. 22, 2019, which is acontinuation of U.S. application Ser. No. 14/876,382 filed Oct. 6, 2015,the disclosures of each of which are hereby incorporated by reference asif fully restated.

TECHNICAL FIELD

Embodiments of the present invention generally relate to touch screendisplays.

BACKGROUND AND SUMMARY OF THE INVENTION

Electronic touch panel displays are used in many commercial applicationsincluding ATMs, automobiles, informational displays, personal computers,cell phones, and the like. Such displays are advantageous as the contentmay be easily changed and the displays are interactive. In manyapplications having an electronic touch panel display is desirable, butin some applications the need for redundancy has slowed the use of suchdisplays.

Examples of such applications include, but are not limited to,commercial aviation, space flight, and military applications, whereredundancy measures are demanded to ensure continued performance ofequipment in the event of a partial failure. In these and otherapplications there may also be visibility requirements to ensureperformance under extreme environmental conditions. These may includeability to withstand high levels of solar loading and visibility inbright ambient conditions. Such stringent requirements are demandedbecause of the possible consequences of failure. Therefore, it isdesirable to provide an electronic touch panel display meetingvisibility requirements and having redundancy measures.

Finally, in these and other applications, electromagnetic interference(EMI) and EMC may become an issue as there are often multiple pieces ofelectronic equipment operating in close proximity. Each device may emitelectromagnetic energy, which can cause EMI with the operation of theother unit that may result in interrupted performance. EMC is theability for multiple devices to work in the same electromagneticenvironment. Therefore, it is additionally desirable to provide theaforementioned electronic touch panel display also having EMC endurancecapabilities that limit EMI.

Exemplary embodiments of the present invention may comprise anelectronic display housed in a sealed gasket with a resistive touchpanel having redundant sensors and input/output devices. The gasket mayprevent the display from being compromised by harsh environmentalconditions. The display may additionally be comprised of multiple layersadapted to withstand high solar loading and remain visible in highambient sunlight environments, such as by use of an active matrix liquidcrystal display (AMLCD). This display may provide one large, contiguousvideo image or may provide multiple, independent video images.

The touch panel may comprise circuitry configured to limit EMI andimprove EMC. The assembly may additionally comprise shielding betweenlayers of the display and in the channels associated with the display,which also limits EMI and improves EMC.

At least two seamless, adjoining grid sections and corresponding touchsensors capable of determining touch screen input are utilized, thusproviding a seamless display and interaction experience when viewed andutilized. This also makes the touch panel redundant. For example,without limitation in the event of a failure of one of the grids or thecorresponding sensors, the display may automatically shift to displayimages only on the portion of the display covered by the remainingoperable grid/sensor. Further, at least two input/output devices areutilized to ensure that each portion of the display and touch panel canbe driven independently from either input/output device. These twomeasures provide redundancy and preserve the operability of the displayunder partial failure.

The display may be made such that it is adapted to comply with militaryspecifications for use in military applications, such as aviation.

BRIEF DESCRIPTION OF THE DRAWINGS

In addition to the features mentioned above, other aspects of thepresent invention will be readily apparent from the followingdescriptions of the drawings and exemplary embodiments, wherein likereference numerals across the several views refer to identical orequivalent features, and wherein:

FIG. 1 is a top perspective view of an exemplary embodiment of thepresent invention;

FIG. 2 is a top view of the device of FIG. 1 ;

FIG. 3 is a side view of the device of FIG. 1 , additionally indicatingDetail A;

FIG. 4 is a detailed side view of Detail A of FIG. 3 ;

FIG. 5 is a detailed side view of the device of FIG. 1 , illustratedwith a stylus contacting the touch panel;

FIG. 6 is a top view of another exemplary embodiment of the presentinvention;

FIG. 7 is a side view of the device of FIG. 6 , also indicating DetailB;

FIG. 8 is a detailed side view of Detail B as indicated in FIG. 7 ;

FIG. 9 is a top view of an exemplary embodiment of the touch panel inaccordance the present invention;

FIG. 10 is an exploded detailed side sectional view of an exemplaryembodiment of a display panel in accordance with the present invention;

FIG. 11 is a plan view of an exemplary circuit in accordance with thepresent invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which exemplary embodiments of the inventionare shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, the size and relative sizes of layers and regions may beexaggerated for clarity.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof.

Embodiments of the invention are described herein with reference toillustrations that are schematic illustrations of idealized embodiments(and intermediate structures) of the invention. As such, variations fromthe shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, are to be expected. Thus,embodiments of the invention should not be construed as limited to theparticular shapes of regions illustrated herein but are to includedeviations in shapes that result, for example, from manufacturing.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 through FIG. 5 illustrates an exemplary embodiment of the presentinvention. An electronic display and touch screen assembly 10(hereinafter the “assembly”) is comprised of a touch panel 14 locatedimmediately above and extending in parallel with an electronic display16. In exemplary embodiments of the present invention the electronicdisplay 16 is a normally black liquid crystal display (LCD), such as theAMLCD. Other electronic displays 16 such as plasma, Light Emitting Diode(LED), Cathode Ray Tube (CRT), and the like are contemplated. Inexemplary embodiments of the present invention, the assembly 10 andrelated components, including but not limited to the electronic display16, support 2560×1024 pixels resolution.

As will be explained in greater detail in subsequent figures, the touchpanel 14 is a resistive touch panel. The touch panel 14 may be wetlaminated to the electronic display 16 and a gasket 12 may be providedthat frames the two layers and creates a seal between the touch panel 14and the electronic display 16. Thereby protecting the assembly 10 fromharsh environmental conditions and providing durability. Other knownmethods of joining the touch panel 14 and the electronic display 16 arecontemplated. The assembly 10 may include a heating device (not shown)for the electronic display 16 that permits the assembly 10 to operate inextreme conditions such as cold weather environments. The touch panel 14may be in electronic communication with the electronic display 16 byflexible circuit, or the like.

As best illustrated in FIG. 2 through FIG. 4 , the assembly 10 mayadditionally comprise a channel 18. The channel 18 may extend from anyside of the assembly 10 or from the back thereof. The channel 18 may beadapted to house a pair of independent input/output devices (not shown).When both input/output devices are operable, each may provideinput/output signals for a respective portion of the electronic display16. In exemplary embodiments of the present invention, each input/outputdevice controls substantially half of the electronic display 16. Thisprovides a redundancy measure. Should one input/output device fail, theremaining operable input/output device may provide input/output signalsfor the remaining portion of the electronic display 16 and thus maintainthe operability of the assembly 10. In other exemplary embodiments ofthe present invention, each input/output device is capable of providinginput/output for the entire electronic display 16.

As best illustrated in FIG. 5 the touch panel 14 may be comprised of twospaced apart surfaces where a top circuit layer 14A is spaced apart froma bottom circuit layer 14B. The two layers extend over the same surfaceand are substantially parallel. They may be spaced apart by theirplacement within a housing, such as the gasket 12. Alternatively, thetop 14A and bottom circuit layers 14B may be spaced apart by individualspacer elements (not shown). The top circuit layer 14A is sufficientlyflexible such when contacted under sufficient force by a stylus 20, thetop circuit layer 14A flexes to contact the bottom circuit layer 14B.Such exemplary operation is illustrated at a contact point 22. The topcircuit layer 14A may be sufficiently elastic, however, to return to itsoriginal position after the force of the stylus 20 is removed. Thestylus 20 may be a human finger, including a gloved hand, or anartificial device.

FIG. 6 through FIG. 8 illustrate another exemplary embodiment of anelectronic display and touch screen assembly 100 (hereinafter the“assembly”) in accordance with the present invention. The assembly 100may be comprised of a touch panel 114 located immediately above andextending in parallel with an electronic display 112.

As will be explained in greater detail in subsequent figures, the touchpanel 114 is a multi-touch resistive touch panel. The touch panel 114may be comprised of a top circuit layer 118 and a bottom circuit layer120. The top and bottom circuit layers 118 and 120 may be spaced apartor immediately adjacent to one another. Additionally, the top and bottomcircuit layers 118 and 120 may be located spaced apart from orimmediately adjacent to the electronic display 112. The touch panel 114may be wet laminated to the electronic display 112 and a gasket 12 maybe provided that frames the two layers and creates a seal between thetouch panel 114 and the electronic display 112. Thereby protecting theassembly 100 from harsh environmental conditions and providingdurability. Other known methods of joining the touch panel 114 and theelectronic display 112 are contemplated. The assembly 100 may include aheating device (not shown) that permits the assembly 100 to operate inextreme conditions such as cold weather environments. The touch panel114 may be in electronic communication with the electronic display 112by flexible circuit, or the like.

The assembly 100 may additionally comprise a series of channels 116. Thechannels 116 may comprise shielding configured to reduce or eliminateEMI and promote EMC. In exemplary embodiment of the present invention,the assembly 100 comprises four channels 116, a pair of which eachextend from the left and right sides of the assembly, respectively.However, any number of channels 116 extending from any part of theassembly 100 is contemplated. The channel 116 may be adapted to house apair of independent input/output devices (not shown), each extendingthough one of the channels 116. When both input/output devices areoperable, each may provide input/output signals for a respective portionof the assembly 100. In exemplary embodiments of the present invention,each input/output devices controls substantially half of the assembly100. In such an embodiment, if one input/output device fails, theremaining operable input/output device may provide input/output signalsfor the remaining half the assembly 100 and thus maintain operability.However, in other exemplary embodiments of the present invention, eachinput/output device is capable of providing input/output for the entireassembly 100. This provides a redundancy measure. In such an embodiment,if one input/output device fails, the remaining operable input/outputdevice may provide input/output signals for the assembly 100 and thusmaintain operability.

In exemplary embodiments of the present invention, the assembly 100 andrelated components are configured to remain operable in atmosphericpressure conditions ranging from sea level to 55,000 feet altitude,including with a rate of change up to 120 feet per second. Similarly,the assembly 100 and related components are configured to withstand 95%humidity, temperature changes between 55 and 90 degrees Celsius (C) at arate of 40 degrees C. per minute with a maximum operating temperature of−45 degrees C. to 71 degrees C. and prolonged storage temperatures of−55 degrees C. to over 90 degrees C. All coatings and materials in theassembly 100 may be configured to withstand, without degradation,commonly used solvents such as water, acetone, lacquer thinner, opticaladhesive, and the like. Similarly, all coatings and materials in theassembly 100 may be configured to withstand, without degradation,commonly used cleaners such as ammonia, detergent, soap, and the like.

FIG. 9 is a front view of an exemplary touch panel 200 in accordancewith the present invention. The touch panel 200 may comprise a grid 216of vertically and horizontally extending electrodes. In exemplaryembodiments of the present invention, the grid 216 may be comprised oftwo adjoining, seamless 8×10 sections formed by the vertically andhorizontally extending electrodes, effectively providing an 8×20 gridand defining a first and a second grid section. Each of the first andsecond grid sections may be operated by an independent input/outputdevice. In exemplary embodiments of the present invention, each of thefirst and the second grid sections corresponds to substantially half ofthe touch panel 200. It is notable, however, that any size grid 216having any number of vertically and horizontally extending electrodesand corresponding grid sections are contemplated. The grid 216 may besurrounded by a series of receivers 210, 212, 214, 218, 220, and 222.The pair of receivers 214 and 222 may extend along the right and leftedges of the grid 216, respectively. The pair receivers 210 and 212 mayextend along the left and the right portions of the upper edge of thegrid 216, respectively. Finally, the pair of receivers 220 and 218 mayextend along the left and the right portions of the lower edge of thegrid 216, respectively.

In an exemplary embodiment of the present invention, the receivers 210,220, and 222 may be placed to receive signals generated by touching thefirst grid section. Likewise, the receivers 212, 214, and 218 may beplaced to receive signals generated by touching the second grid section.The grid 216 is sized to cover the entirety of the electronic display16. The vertically extending receivers 222 and 214 may be configured toreceive input regarding the vertical (Y) position of the input.Similarly, the horizontally extending receivers 210, 212, 218, and 220may be configured to receive input regarding the horizontal (X) positionof the input.

In exemplary embodiments of the present invention, each of thevertically extending receivers 222 and 214 may be capable of receivinginput signals regarding the Y position of the input from both the firstand second grid section. The horizontally extending receivers 210 and220 may be capable of receiving input signals regarding the X positionof the input from the first grid section. Similarly, the horizontallyextending receivers 212 and 218 may be capable of receiving inputsignals regarding the X position of the input from the second gridsection.

The grid 216 and the receivers 210, 212, 214, 218, 220, and 222 may beconfigured to respond to a stylus, a human finger, or a gloved hand. Thegrid 216 and the receivers 210, 212, 214, 218, 220, and 222 may beconfigured to respond to an activation pressure of under 0.8 N and mayallow for multiple touch inputs to be measured simultaneously.

The first and second grid sections and corresponding receivers providesa redundancy measure. When both the first and the second grid sectionsare operable, the entire touch panel 200 may be utilized. Should one ofthe first or the second grid sections or the corresponding receivers berendered inoperable, the remaining operable grid section may accepttouch input for the portion of the grid 212 that it controls. Forexample, if the receiver 210, 222, and/or 220 should fail, the imagethat was being shown on the electronic display 112 may be shifted ontojust the portion of the electronic display 112 corresponding to theremaining operable first or second grid sections such that the assembly100 remains fully functional, albeit over a smaller area. In otherexemplary embodiments, in such circumstances half of the assembly 100may remain operable and the image may not be shifted.

It is notable that while the touch panel 200 may be described in termsof operating with a particular embodiment described herein, it iscontemplated that the touch panel 200 may be utilized with any of theembodiments described herein.

As will be discussed in greater detail in subsequent figures, the touchpanel 200 may be utilized in conjunction with a bottom glass layer 320of an exemplary display panel 300 illustrated in FIG. 10 , and each lineof the touch panel 200 grid 216 may comprise an exemplary circuit 400,such as the one illustrated in FIG. 11 .

In one exemplary embodiment of the present invention, the touch panelactive area may be 506.88 mm×202.75 mm and the activation force neededmay be in the range of 0.05 N-0.8 N and may provide a minimum of twopoint multi-touch, and may have an operating life of over 1 millionhits. In other embodiments of the present invention all of the abovedimensions and values may change to the desire of the user ormanufacturer.

FIG. 10 is an exploded detailed side sectional view of the exemplarydisplay panel 300 in accordance with the present invention, such for usewith the electronic display 16. A cover glass 310 may form the top layerof the display panel 300. The cover glass 310 may comprise ananti-smudge, anti-reflective coating. A linear polarizer 312 followed bya quarter wave retarder 314 may be located below the cover glass 310 andabove a top glass 316. The quarter wave retarder 314 may be configuredto withstand high temperatures. An optically clear adhesive (OCA) layer318 may be placed between the top glass 316 and the bottom glass 320.

The bottom glass 320 may be located below the top glass 316 but above anindium tin oxide (ITO) layer 322. In exemplary embodiments of thepresent invention, the touch panel 200 will be located in the bottomglass 320 layer. The ITO layer 322 may be located immediately below andbe affixed to the bottom glass 320. The ITO layer 322 may act as an EMIshielding layer, thus promoting EMC. In exemplary embodiments of thepresent invention, the ITO layer 322 may extend beyond the bottom glass320 by 3 mm on all sides. Finally, a final quarter wave retarder 324 mayform the bottom layer of the display 300. The final quarter waveretarder 324 may have a smaller area than the previous layers, which mayall have substantially the same surface area. Such a configurationpermits the display panel 300 to be visible in high ambient lightconditions and operable under high levels of solar loading. In exemplaryembodiments of the present invention the display panel 300, the assembly100, and other related components shall be configured to withstandprolonged exposure to solar radiation with a normal flux of 260 BTU/ft²at sea level atmospheric pressure and 55 degrees C.

Each of these layers may extend in parallel with the other layers. Eachof these layers may also be spaced apart from one another and be ofvarious thicknesses. In exemplary embodiments of the present invention,the layers may be immediately adjacent to, secured to, or integrallyformed with one another. In exemplary embodiments of the presentinvention, the cover glass 310 may be a 0.15 mm micro sheet. In otherembodiments, the cover glass 310 may be 0.5 mm thick. The top glass 316may also be 0.15 mm thick, while the bottom glass may be 1.1 mm thick.The ITO layer 322 may be 3 mm thick. While these thicknesses areexemplary, they are not intended to be limiting, any functionalthicknesses are contemplated. It is also notable that adhesive layersmay be placed between any of the layers of the display panel 300.

It is notable that while exemplary display panel 300 may be described interms of operating with a particular embodiment described herein, it iscontemplated that the display panel 300 may be utilized with any of theembodiments described herein.

FIG. 11 illustrates an exemplary circuit 400 in accordance with thepresent invention. The exemplary circuit 400 is configured to minimizeEMI and maximize EMC. Each line of the grid 216 of the touch panel 220may be comprised of the circuit 400. Therefore, it is contemplated thatany number of the circuits 400 may be utilized in communication with oneanother.

The circuit 400 may be used with the assembly 10 or the assembly 100 inconjunction with the touch panels 14 and 114, respectively. It isnotable that while exemplary circuit 400 may be described in terms ofoperating with a particular embodiment described herein, it iscontemplated that the circuit 400 may be utilized with any of theembodiments described herein.

The circuit 400 may comprise a pair of zener diodes 410 in parallel withand located on either side of a series of capacitors 412. An inductor416 may be placed in series between each capacitor 412. In exemplaryembodiments of the present invention, three capacitors 412 are placed inparallel, and an inductor 416 is placed in series between each of saidcapacitors 412. Other arrangements are contemplated.

Having shown and described a preferred embodiment of the invention,those skilled in the art will realize that many variations andmodifications may be made to affect the described invention and still bewithin the scope of the claimed invention. Additionally, many of theelements indicated above may be altered or replaced by differentelements which will provide the same result and fall within the spiritof the claimed invention. It is the intention, therefore, to limit theinvention only as indicated by the scope of the claims.

What is claimed is:
 1. A touch panel assembly adapted to reduce electromagnetic interference, said assembly comprising: a housing adapted to be secured within an instrument panel of a vehicle; an electronic display within said housing, adapted to display an image; a resistive touch panel in association with said display, comprising first and second independently operable, seamless grid sections and a plurality of touch input receivers placed adjacent to said first and second grid sections; at least one electromagnetically shielded channel extending from within said housing to outside of said housing; a first input/output device in electronic communication with said display in association with said first grid section, and extending through the at least one electromagnetically shielded channel; and, a second input/output device in electronic communication with said display in association with said second grid section, and extending through the at least one electromagnetically shielded channel.
 2. The assembly of claim 1 wherein: said resistive touch panel comprises electronic circuits; and each of the electronic circuits comprises: a first terminal; a second terminal; a third terminal; a plurality of zener diodes, each coupled between said first terminal and said third terminal; a first capacitor, coupled between said first terminal and said third terminal; a first inductor coupled between said first terminal and said second terminal; a second inductor coupled between said first terminal and said second terminal, wherein said second inductor is further coupled with said first inductor; and a second capacitor coupled between said first terminal and said third terminal, wherein said second capacitor is further coupled with said first and second inductors.
 3. The assembly of claim 1 wherein: the electronic display comprises liquid crystals.
 4. The assembly of claim 1 further comprising: a controller having executable software instructions, which when executed, configure the controller to: display the image spread across both the first and second grid sections of the electronic display; monitor for failure of one of said first and second grid sections; and upon failure of one of said first and second grid sections, automatically display the image across an operable one of said first and said second grid sections.
 5. The assembly of claim 1 wherein: at least two of said input/output devices are in electrical connection with said first grid section and at least two others of said input/output devices are in electrical connection with said second grid section.
 6. The assembly of claim 5 further comprising: a controller having executable software instructions, which when executed, configure the controller to: monitor for failure of any of said input/output devices; and upon failure of an input/output device, automatically switch signaling to an operable one of said input/output devices.
 7. The assembly of claim 1 wherein: said display includes a cover layer located above a polarizer, which is located above a top glass, located above an indium tin oxide layer.
 8. The assembly of claim 7 wherein: said housing and said cover layer form a substantially watertight assembly.
 9. The assembly of claim 1 wherein: said electronic display is joined to said resistive touch panel.
 10. The assembly of claim 1 further comprising: a heating device within the assembly, configured to provide heat to the assembly.
 11. The assembly of claim 1 wherein: said touch panel electronically senses activation pressures above and below 0.8 N.
 12. The assembly of claim 1 wherein: said touch panel is configured to substantially instantaneously respond to multiple simultaneous touches.
 13. The assembly of claim 1 wherein: each of said grid sections comprise an electrical circuit having zener diodes connected in parallel with a plurality of capacitors, and inductors connected in series with the capacitors.
 14. The assembly of claim 13 wherein: the number of capacitors is three and the number of inductors is three.
 15. A touch panel assembly for use in a commercial, military, or private vehicle, said touch panel assembly comprising: a housing adapted to be secured within an instrument cluster of a commercial, military, or private vehicle; an electronic display located within said housing and comprising: a cover layer; a linear polarizer located below the cover layer; a liquid crystal electronic display layer adapted to display an image; a touch panel comprising first and second independently operable, seamless grid sections corresponding to first and second areas on said display layer, and a number of touch input receivers placed adjacent to said first and second independently operable, seamless grid sections; a bottom layer located below the touch panel; an indium tin oxide layer located below the bottom layer; a number of input/output devices in communication with said touch panel; a controller having executable software instructions, which when executed, configure the controller to: display the image across substantially an entirety of the electronic display layer; monitor for failure of one of said grid sections; and upon failure of one of said grid sections, display the image on a portion of the electronic display corresponding with an operable one of said grid sections.
 16. An electronic display assembly, said assembly comprising: a housing adapted to be secured within a dashboard of a vehicle; an electronic display subassembly secured within said housing, said subassembly comprising an electronic display layer adapted to display an image, said display layer having independently electronically operable first and second sections, wherein said first and second sections are located adjacent to one another to present a seamless appearance to a user; a first input/output device in electrical connection with said first section; a second input/output device in electrical connection with said second section; and a controller, having executable software instructions which when executed configure the controller to: display the entire image across the first and second sections when both sections are operable; monitor the first and second sections to determine if either section is non-operable; and automatically display the entire image on the operable section when one of the sections is non-operable. 